Season 6: Episode 1: The Date Night Variable

Howard is still in space, but he's able to connect with the group on earth via webcam. During a call with Bernadette, he's caught in an argument between his wife and his mother over the topic of where he'll live when he gets back. Meanwhile, Raj is feeling very lonely while Wolowitz is away, so he tries to tag along with the two other couples (Sheldon/Amy & Penny/Leonard).